Automatic telephone system



Aug. 7, 192s. Y 1,679,522Y N G. vGRABE AUTOMATIC TELEPHONE SYSTEM Filed oct. e. 1921 Esnr Erable i ab UNITED NSTATES PATENT .oFi=,lcE`.

GECRG enana, or NIKCLAssEE., NEAR BERLIN, GERMANY, nssIGnoP., BY MESNE .AssIGNMENrs, To AUTOMATIC ELECTRIC INC., or CHICAGO, ILLINOIS, A couronn- TIO'N 0F DELAWARE.

AUTOMATIC TELEPHONE SYSTEM.

Application led October 8, 1921, Serial No. 506,424, and in Germany October ,11, 1920.

, connections in automatic `or semi-automatic telephone installations. Certain' of the selecting devices used for making the connecltions are `set on a line or group of lines by means of numeral current impulses emitted by a sendinginstrument. In the latter case the selecting devices automatically seek a disengaged line. Selectors are also provided which, like the pre-selectors, exercise a free selection. Now the contingency may arise that numeral impulses are sent out from the sending instrument before these lecting device in front of the numerical switch has completeda free selection which it is executing. In such a case the numerical switch will only receive a 'portionjof the series-of impulses, and will, in consequence, be set onaline or group oflines other than that desired.

To obviate this drawback according to the invention theselecting devices are provided with means which prevent the completion of a partly established connection in the event of a series of numerical impulses `being emitted from the Calling station before the automatic trunk or free selection is completed. ranged that, when the first numeral impulse comes into operation, the selectingr device that is in the act of setting comes to a standstill and the testing is prevented, whilst at the same time a signal (e. g. a buzzer signal) is transmitted to the calling subscriber.

It may frequently happen that mechanical defects or contamination may retard the set# ting action of the selecting device exercising freerselection. To enable dimmediate identi-- ication of the selecting .devices that are working properl the circuits are arranged ,to prevent the re ease of the selecting devices that have already been set, this being preferably effected at the moment the first numeral `impulse comes into action. At the same time a control signal "isswitched on, which indicates the selecting device into which,`

numeral impulseshave gained access before the free selection has been completed. By

, preventing the release of the already setseecting devices, the calling subscribers line can also be `identified atfthesame time, so

The circuits are preferably so ar-V relay Vl at the contact 3,..

that, if the selectors are in good order, the Impulse sender can be examined, since -it may cause faults by running oii too quickly.

The drawing illustrates two dilierent embodiments ot the invention, a selector being represented in both cases.` The invention is amt, however, restricted to selectors, since each pre-selector may be provided with a switch device preventing the completion of the connection in the event of numeral impulses being'emitted before free selection has been completed.

Fig. l shows a selector GIV, which may be mechanically of the well known Strowger type. I The circuits in this figure illustrate one embodiment of the invention. f

Fig. 2 shows a selector GIV which is similar to the selector GWV except that the cir- 'cuits have been slightly altered in order tov illustrate a second embodiment of the invention. i

The switch arrangement according to Fig. l operates in the following' manner:

When the selector GrllVv is engaged, the relay() operates through the c-coMnductor, winding I of C, 7k, earth, so that the contacts 1,., 10c, 15C and 32 ot' this ,relay are ground by way of 2m and resist-ance R to test lead c to make this lead busy to other selecting devices.

p If numeral impulses be emitted from the callers instrument `the impulse relay A is rendered intermittently dead in Iaccordance with the impulses. Hence, each time the contact 5a otthe relay A is closed, the lifting magnet II is energized as follows: earth, 32,., 26p, 4,1, 5., V2,

Gn, H, battery, earth. In this manner, the

selector is liftedto the desired group of lines in accordance with the number of the numeral impulses. "At the first lifting movement the contact 7k was opened,whilst the `contacts Stand 9k were closed. During lll LLI

the series of impulses for lifting the selector, the relay V2 remains energized, and only drops when the contact 5a has remained open forsome time after the series of impulses has come to an end. lVhen the relay V2 drops, its contact 12n closes, so that the rotary magnet D is energized through: earth, 10... llvl, 12%, 13p, D, 8,., battery, earth.

The selector is now set in rotary mot-ion and begins to'tcst. It itv finds a. disengaged line, the testing relay P operates through: earth, lnittcry, ll-.m 15,.. windings ll and l. ot P, 0 (1,. earth. Thetesting relay operates. shortv circuits its high-resistance winding Il at. the contact 16 and thus blocks the engaged line against .engagcnicnt by another selecting device. Furthermore, the relay P opens the circuit ot the rotary magnet D at the contact 13W and the circuit of the release magnet M at the contact l7; and,` in addition the speaking leads are switched tln'ough-the impulse relay A being shut outby opening the contacts 18p and 19,., and closing the contacts 20,. and 2l.

. The opening of the contact QGn prevents the switching on ofthe winding ll of the relay C. T he impulse relay A, which drops when the contacts 18 and 19,. are opened, opens its contact 3M so that. the slow acting relay V, is also rendered dead and closes its contact 22,1l

The release of the selecting device on the termination of the conversation is etiectcd` in known manner by interrupting the current through the lead 0,. The falling relay P completes, via 17p, the circuit for the release magnet M, since the contact 22W was already closed, in the above described manner, in switching through the speaking leads. The release magnet M operates, interrupts the. current through the lead c by opening the contact. 2m, and releases the selector.

The case will now be considered in which numeral impulses have been emitted While the selector is still seeking a disengaged line. At. the first rotary movement of the selecting device the rotary contact Gn is opened and the rotary contact. Q3 closed. It the relay A be fle-energized by impulses during the rotation of the selecting device, then, as soon as the `contact 5,L is closed by the tirst` impulse, the vwinding ll of the relay C is energized by way 4ot the contact 23u. Thiswinding is in differential connection with the winding I. The windings counteract each other and the relay C becomes dead.

lhen the relay C drops, lits contacts lc, c, A

c and 32e are opened, thus interrupting the holdin the relay stoppingr the selecting device, preventing the testing, and switching olf the winding Il of C. The switching ott' of the winding Il ot C is necessary in order to avoid re-energizing of C by the second imcircuit through winding I oli'- pulse, since when this impulse occurs the winding l is no longer energized. Moreover an engaged buzzer BS is connected to the winding lll ot the impulse relay A at the contact 24,. of relay C, through the rotary Contact Q5, which is closed on the first rotary movement. The subscriber hears the engaged77 signal. lVhen he hangs up the receiver, the impulse relay A becomes dead, opening its contact: 3 so that the slowacting relay V, drops and closes its Contactl 22,.. This switches on the release magnet M which releases the selecting device.

`The swicth arrangen'ient illustrated in Fig. Q corresponds in general to the arrangement in Fig. l. but differs therefrom in thatl the selecting device is not released by hanging up the receiver at the calling instrument. lVith this object. in the arrangement according to Fig. Q. the circuit. ot the relase magnet M is alsointluenced by a contact @th of the relay C. It the relay C is rileeucrgized in the above manner while the selecting device is seeking a disengaged line, the contact QS.. opens` and eonsermently the release magnet M cannot be energized even after the closing ot the Contact 22 Moreover, on the dropping ot the relay C, a. control lamp Cl) is switched on through the contact 29,., of the relay V1, rotary contact and contact 8l, of relay C, thus indicating to the exchange operator which of the selecting devices ha.l not been released. Owing to the non-rclease ot the selecting device, the current through the incoming lead c is not interrupted, so that the pre-arranged selecting devices rcmain set.

That l claim and desire to secure by Letters Patent iszl. ln a telephone system, a switch, wipers for said switch, means for transmitting a set o'f impulses to said switch for dircctively operating said wipers, means for auton'iatically operating said wipers, means controllable from a calling liuc tor releasing the. switch, and means responsive to another set ol'A impulses transn'iitted to said switch before the second named means has completed its operation llor locking said switch in operated po sition independent of control from the callingv line.

2. In a telephone system, a switch, wipers tor said switch, means l'or transmitting a set of impulses to said switch lor (lirectively operating said wipers, mcans for automatically operating said wipers, means controllable from a calling line `for releasing the switch, and means responsive to another set ot impulses transmitted to said switch before the last named means has completed its opera tion for locking up said switch independent of control from the calling line and for operating a signal.

3. In an automatic telephone system, a sefill jul

tion of the relays to set the selector' into hunting relation to the line terminals and seize the first idle one encountered, and relay means comprising only said relays for disabling theselector from seizing Vresponsive to the control means being operated While the selector is hunting.

5. In ,an automati'cvtelephone system, a Wiper selector, relays of the selector, a group of line terminals accessible `from the selector, remotecontrol means -for causing Vthe operation of th relays to set the selector into hunting re ation to the line terminals and seize the first idle o'ne encountered, and relay meansomprising only saidrelays for disabling the selector from continuing its hunting operation responsivel to operating the control means While the selector is huntlng. .Y k v (i. In an automatic vtelephone system, a Wiper selector, relays of the selector, a group of line terminals accessible from the selector, remoteontrol Lineans for causing the opera tion of the relays to set the selector into hunting relation to the line terminals and seize the first idle one encountered, and means for disabling the selector from continuing its hunting operation responsive to operating the control means While the selector is hunting.

7. In an automatic telephonesystem, a Wiper selector, relays of the selector, a group of line terminals accessible from the selector, remote control means for causing the operation of the relays to set the selector into hunting relation to the line terminals and seize the first idle one encountered, and means responsive to the control means for stopping the hunting operation Without restoring the selector.

8. In an automatic telephone system, a calling line, a. selector, relays for operating the selector, a group of line terminals ac; cessible from the selector, control means operated over the calling line for causing the operation of the relays to set the selector into hunting relation to the line terminals and seize the first idleone encountered, and relay means comprising only said relays for disabling the selector from seizing responsiye tol the control means being operated warner@ areaal-rehearing 9. In a te ephone system, a calling line, a selector, relays of the selector", a group of line terminals accessible from the selector', directive control means ontlre calling line for operating certain of the lrelays to set the selector' With selective relation to the group, means for causing certain of the relays to Atherearter operate the selector" in hunting relation ivith the4 group and seize the lir'st idle terminal found, and relay means comprising only said before operated relays for disabling the selector' from seizing responsive to the control means being operated. While the selector is hr'uiting. ,4

In a telephone system, a callingline, a selector, relays of the selector, groups or' line terminals accessible from the selector,

directive control means on the calling line for operating certain of the relays to set the selector ivith selective relation to adesred group, means for causing certain' oi the relays `to thereafter operate the selector in hunting relation with Ythe group' and seize the lirst idle terminal found, and relay means comprising only said before operated relays lor disabling` the selector romseizk ing responsive to the control means being Operaied while the selector is hunting. A

l1, In a telephone system, a calling line, a Selector, relays of the selector, a tone source, a group of ine terminals accessible from the selector, automatic'control means for caiising the operation of the relays to set the selector .into ,hunting relation to the line terminalsra'nd s'eize the' first idle one encountered, and relay means comprising only said relays for applying the tone source to the calling line responsive to the control means being operated while the selector' is hunting.

12. In a telephone system, a calling line, a selector, relays of the selector, a ltone source, a group of line terminals accessible from the selector, automatic control means for causing the operation of the relays to set the selector into hunting relation to the line terminals and seize the first idle one encountered, and relay means comprising only said relays for applying the tone source to the calling line and for disabling the selector" from seizing responsive to the control means being operated While the selector is huntrn.

13. In a telephone system, a calling line,

a trunk line terminating in an automatic switch having a primary and a secondary movement, trunk lines accessible to said switch, means controlled trom said calling line for seizing said trunk line and for causing said switch to operate successively in its prima-ry and secondary movements to select an idle one of said trunk lines, means for sending impulses over said calling line, and means operative responsive to said impulses being sent before said switch has connected with an idle trunk for placing a busy tone on said calling line and for stopping the secondary movement of said switch.

14. In a telephone system, a calling line, a trunk line terminating in two motion automatic switch, trunk lines accessible to said switch, means controlled by said line for seizing said trunk line and for causing said switch to operate in its two motions successively to select an idle one oi said trunk lilies, means for sending impulses over said calling line, and means operative responsive to said impulses heing sent before said switch has connected with an idle trunk for stopping the movement ot said switch.

15. In a telephone system, a plurality of lines, an automatic switch, trunks accessible to the switch, means lor extending a connection from a calling line to the switch, means :t'or transmitting a group of digit impulses to the switch, means in the switch responsive to the digit impulses for operating the same, means responsive to the cessation of the group ot impulses for causing the switch to hunt lor a trunk, and means ell'ective responsive to another group of' im pulses being transmitted to the switch prior to the cessation of the hunting movement of the switch for maintaining the connection between the calling line and said switch independent o control over the calling line to enable the attendant to identify the calling line.

16. A telephone system wherein any one of a plurality ot lines may be connected to any one of a plurality of automatic switches, trunks accessible to each of the switches,

each switch including means for selecting an idle trunk, said means comprising means controlled by a group ot' digit impulses to select a group of lines and auton'iatically controlled responsive to the cessation 0f the group ot impulses to select an idle trunk in the group, and means elleclive responsive to a subsequent group of inipulses transmitted to the switch prior t0 the termination of the automatic movement ot the switch for maintaining the connection between the callin" line and said switch independent of contro over the calling line to enable the attendant to identity the particular ailing line and the particular switch.

17. A telephone system wherein any one of a plurality ot lines may he connected to any one of a plurality of automatic switches, trunis accessible to each ot' the switches, each switch including means for selecting an idle trunk, said means comprising means controlled by a group ot digit impulses to select a group ot lines and automatically controlled responsive to the cessation of the group et impulses to select an idle trunk in the group, and means elfective responsive to a subsequent group of impulses transmitted to the switch prior to the termination ol the automatic movement of the switch l'or maintaining the switch operated independent of control over the calling line, to enable the attendant to identify the switch.

lin witness whereof, I hereunto subscribe my name this 1-lth day of September, A. D. 1921.

. GEORG GRABE. 

